<template>
  <div class='contain'>
    媒体查询--如果文档宽度小于 300 像素则修改背景颜色
  </div>
</template>
<script>
  import helper from '../../service/helper.js';
  import parameter from '../../service/state.js';
  export default {
    data() {
      return {

      };
    },
    components: {

    },
    methods: {

    },
    watch: {

    },
    mounted() {

    },
};
</script>
<style scoped >
/* 如果文档宽度小于 300 像素则修改背景颜色(background-color): */
@media screen and (max-width: 300px) {
    .contain {
        background-color:lightblue;
    }
}
</style>